Manufacture of ethyl chloride



soda solution.

P'atented Apr. 9, 1946 MANUFA CTURI? OF ETHYL CHLORIDE Eugen GottfriedGalitzensteln, London, and

Cyril Woolf, Flnchley, London, England, assignors to The DistillersCompany Limited, Edinburg, Scotland, as British company No Drawing.Application March 9, 1944, Serial No. 525,758. In Great Britain December28,

'20 Claims. (Cl. ma -652,) It is known that ethyl chloride is formedwhen potassium or barium salts of ethyl sulphuric acid are treated withhydrogen chloride (Berichte der Deutschen Chemischen Gesellschaft 1878,11, 1929) In British specification No. 370,211 there is described aprocess in which ethyl chloride is produced when ethyl sulphuric acid iscaused to react with aqueous hydrochloric acid at temperatures exceeding100 C. and at elevated pressures such as 24 atmospheres.

We have found that ethyl chloride can be produced satisfactorilyaccording to the present invention by reacting gaseous hydrogen chloridewith preformed sulphuric esters of ethyl alcohol in the presence of acompound oiantimony, bismuth or tin as catalyst at temperatures between40 and 110 C. The chlorides, oxides, sulphates or carbonates ofantimony, bismuthandtin may be used.

The reaction between ethyl hydrogen sulphate and hydrogen chlorideproceeds according to the equation:

( l) C2H5.HSO4+HCI=C2H5C1+H2SO4 and can be carried out at normalpressure.

Instead of ethyl sulphuric acid, diethyl sulphate can be used. We havefound that when ethyl chloride is produced by the interaction ofhydrogen chloride and diethyl sulphate in the presence of compounds ofantimony, bismuth or tin, the initiation of thereaction is facilitatedby the presence of some free sulphuric acid in the reaction mixture atthe commencement of the reaction. The probable function of thi freesulphuric acid is to cause the-formation of ethyl sulphuric acidaccording to the equattionz The following examples illustrate theprocess of the invention as a batch process:

Example I A stirring flask was charged with 214 grams ethyl sulphuricacid.- 14 grams of anhydrous antimony trichlorlde were added and dryhydrogen chloride was then introduced at the rate of about 8 grams perhour whilst maintaining the liquid at a temperature of 90 C. Stirringwas continued throughout the operation. The vapours escaping from thestirring flask consisted of ethylchloride accompanied by some excess ofhydrogen chloride which was removed from the ethyl chloride by washingwith water and then with caustic The vapours of ethyl chloride weredried with calcium chloride and then condensed out. The yield of pureethylchloridaobtained over a period of ten hours was 102 grams or 93 Percent of the theory.

Example II Into a stirred mixture of 220-gra1ns diethylsulphate, 36grams sulphuric acid (98 per cent) and 6 grams bismuth oxide, dryhydrogen chloride was introduced at the rate of about 6 grams per hourwhilst maintaining a temperature of C. in the reaction liquid. Theescaping gases were washed withwater and then with milk of lime,

dried with calcium chloride and the ethyl chloride condensed out. In 20hours 163 grams of practically pure ethylchloride were collected,- theyield being per cent of the theory.

Example III A stirred mixture of 105 grams diethylsulphate,

'70 grams sulphuric acid (100 per cent) and .17

v reflux condenser. After washing and drying ethylchloride was condensedat the rate of 12 grams per hour.

It will be inferred from Equations 2 and 1 that on completion of thereaction between the esters of sulphuric acid and hydrogen chloride,free sulphuric acid is present together with the metal compounds. Wehave found that the spent liquids resulting from the reaction betweenethyl sulphuric esters and hydrogen chloride have the power of absorbingethylene thus reforming the original sulphuric acid esters. The reformedesters are capable of reacting again with hydrogen chloride to produceethylchloride without the necessity of further addition of compounds ofantimony, bismuth and tin.

Accordingly, therefore, our invention includes a process for themanufacture of ethyl chloride from ethylene. The process consists of anumber of cycles,each cycle comprising two stages. In the first stage;ethylene is absorbed by sulphuric acid. Compounds of antimony, bismuthor tin are addedito the resulting liquid and the second stage of theprocess consists in reacting the mixture with hydrogen chloride toproduce ethyl chloagain absorbedfollowlng which, hydrogen chlo ride isagain passed through th liquid reaction thisconstitutestheseconds sotthesecond cycle. Further cycles are theme as the second cycle.

We prefer to carry. out our process in a sub,- stantially anhydrousmedium using sulphuric acid of between 100 per cent and 95 per cent byweight.

We have found it to be advantageous in the stages of ethylene absorptionto introduce ethyleneuntil the concentration of ethyl groups present (inthe form 01' the sulphuric esters of ethyl alcohol) has reached between0.7 to 1.2 mols .per mol of sulphuric acid. Such mixtures ofdiethylsulphate, ethylsulphul'ic acid and sulphuric acid have been folmdto be the most suitable for the production of ethylchloride. Furthermorewe have found it unnecessary to continue the hydrogen chlorideintroduction to the point of completion of the reaction: we prefer tostop the flow of hydrogen chloride when the rate of ethylchlorideproduction slackens off. This generally occurs when the concentration ofethyl groups has fallen to the neighbourhood of 0.25 mol per mol ofsulphuric acid present in the reaction medium. By leaving some unreactedethyl groups in the solution, the subsequent absorption of ethylene isenhanced, as is already known from prior British specification No.221,512. v

The following examples illustrate the process of liquid showed anincrease in weight of 47 grams corresponding to an absorption of 0.9 molof ethylene per mol of sulphuric acid. The temperature was then raisedto 90' 0., hydrogen chloride was introduced and ethylchloride condensedout of the eilluent gases. When. the production r ate of ethylchloridebegan to decrease, the hydrothe invention as a continuous processconsisting of a number of successive cycles.

Example IV v A stirring vessel was charged with 180 grams sulphuric acid(98 per cent) and 12 grams anhydrous bismuth chloride. v vessel werestirred and maintained at 70" 0. during the whole operation. Dryethylene was introduced at the rate of 11-12 grams per hour for 4 hours.The ethylene supply was then cut off and dry hydrogen chlorideintroduced atthe rate of about 9 grams per hour to start the productionof ethylchloride, When the rate of formation of ethylchloride droppedbelow a figure of 6 grams per hour the introduction of hydrogen chloridewas cut oil, the passage of ethylene was restarted and the second andsubsequent cycles carried out. The results of the entire operation aresummarized in the following table:

The yield of ethyl chloride based on ethylene absorbed was 94 per centof the theory. The reaction liquid was still active after the tenthcycle.

Example V 183 grams of sulphuric acid (100 per cent) containing 12 gramsanhydrous antimony trichloride were heated to 70 C. and ethyleneintroduced whilst stirring until the weight of the reaction The contentsof the gen chloride stream was stopped, the temperature lowered to C.and ethylene introduced (beginning a. second cycle of operations) andthe absorption of ethylene was continued until an increase in weight of38 grams had occurred thus again bringing the total amount of ethylgroups present to- 0.9 mol per mol of sulphuric acid. The subsequentintroduction of hydrogen chloride was carried out at C. Further cyclesfollowed in a way similar to the last cycle. After a working time of 150hours the yield of ethylchloride produced based on ethylene absorbedamounted to 88 per cent of the theory.

Instead of pure ethylene, gas mixtures containing ethylene, e. g.mixtures of ethylene and paraffln hydrocarbons; can be used. We havefound it advantageous to employ elevated pressure in the ethyleneabsorption stage when using ethylene admixed with other gases. Thecorresponding stages of ethylchloride production may be carrled out in aseparate vessel and at ordinary pressure. Previous processes (e. g. thatdescribed in United States speciilcationNo. 2,125,284) relating to thedirect reaction between hydrogen chloride and gas mixtures containingethylene have proved to be technically unsatisfactory as the presence ofinert gaseous substances depresses the rate of formation ofethylchloride and gives rise to dimculties in the recovery of thediluted ethylchloride. However, the ethylchloride obtained by ourprocess, is contaminated only with hydrogen chloride, which is readilyremoved.

Instead of a stirring vesseLother suitable devices can be employed foralternately contacting the liquid reaction medium with ethylene and withhydrogen chloride. For instance the two gases may be alternately passedinto a coil system through which the liquid reaction medium iscirculated at high speed with aid of a pump.

The experiments on which the present invention is based proved that thepresence of compounds of antimony, bismuth or tin is essential for themanufacture of ethylchloride from hydrogen chloride and the ethyl estersof sulphuric acid.

No ethylchloride production could be obtained when working according toUnited States specification No. 2,284,467 'in which there is describedthe production of allqrlchlorides by contacting an olefine and hydrogenchloride with sulphuric acid (97 to 100 per cent) at atmosphericpressure and at a. temperature between room temperature and the freezingpoint of sulphuric acid.

What we claim is:

1. A process for the manufacture of ethyl chloride which comprisesreacting substantially anhydrous gaseous hydrogen chloride with asubstantially anhydrous preformed sulphuric ester of ethyl alcohol inthe presence of free sulphuric acid of a concentration of to and in thepresence of a catalyst of the class consisting of compounds of antimony,tin and bismuth at a temperature between 40 C. and C.

2. A process according to claim 1 wherein said sulphuric ester is ethylhydrogen sulphate.

3. A process according to claim 1 wherein said sulphuric ester isdiethyl sulphate.

4. .A process accordingto claim 1 wherein a ssesu'ro mixture of diethylsulphate and sulphuric acid is employed.

5. A process according to claim 1 wherein seid preformed sulphuric estercontains ethyl groups to a. value between 0.? and 1.2 mole per mol ofsulphuric acid.

6. A process according to claim 1 wherein the feed of hydrogen chlorideis stopped when the content of ethyl groups in the resotion liquid. hesfallen to e value in the neighbourhood of 0.25 mol per moi. of sulphuricacid.

7. A process for the manufacture of ethyl chloride which comprisesreectins suhstentlelly enhydrous gaseous hydrogen chloride with as sub--stsutisliy anhydrous preformed sulphuric ester of ethyl in the presenceoi free sulphuric acid of s. coucentretion oi 95% to 100% and alcohol inthe presence of a. catalyst of the class cousist= ing of compounds ofantimony, tin and hisrnuth at etempereture between 46 C. and 116 C.until the content of ethyl groups in the reaction liquid has fellen to evalue in the neigbourhood oi 0.95 mol per moi of sulphuric sold,stopping the teed oi hydrogen chloride, feeding ethylene into theresctiori liquid to regenerate the sold sulphuric ester-sulphuric ecicimixture eieo theresiter rcstsrtirig; the feed of hydrogen chloride.

t. A process eccordirig to claim 7 wherein the feed of ethylene isstopped when the contest of ethyl groups in the reaction liquid hasresched e value between 0.7 end 1.2 mclsper moi of col phuric acid.

9. is process sccording to cisim '3 wherein the feed of ethylene isstopped when the content oi ethyl groups in the reaction liquid hesreached a. value between 0.? end it: mole per moi of sulphuric acid andthe feed of hydrogen chloride is stopped when the content of ethylgroups in the resctiori liquid has islieu to c. yelue in theneighbourhood of 2.525 mol per mol of sulphuric acid.

' it. it. coutuuous process for the msnuiecture of ethyl chloride whichcomprises elteruste steees of ethylene iced into sulphuric acid of econcert trstion oi 95% to 100% containing? e cartsst of the closeconsisting of cciripounds of antimony, tin and bismuth end gaseoussubstantially snhydrous hydrogen chloride teed. into the subphuricester-sulphuric acid mixture therehy produced at a. temperature of 4.0G. to mm 6.

ii. A. continuous process according to claim 16 wherein the temperatureof the reaction. liquid during? the stage oi ethylene iced is lower thanduring the stage of feedlot hydrogen chloride.

12. A coutiuuous process according: to oleiru it wherein. the stage offeedingethyleue is termimeted when the resection liquid couteius ethylgroups to e value between 0.? sue. 1.2 mole per mol '01 sulphuric sold.

i3. A continuous process sccorciins to cleim 10' wherein the stage orfeeding gaseous hydrogen chloride is terminated when the reaction liquidcontains ethyl groups to e. value in the neighbourhood of @25 mol permol of sulphuric acid.

' re. A continuous process scccrdinr to claim is wherein the ethylenefeed is e mixture of ethylone end so. inert see.

iii. A continuous process according claim it.

wherein the ethylene mixed with inert gas is fed under superstrnosphericpressure.

16..A continuous process for the manufacture of ethyl chloride whichcomprises alternate stages of ethylene feed into sulphuric acid of a.concentretion of 95% to 100% containing a catalyst of the classconsisting of compounds of antimony, tin and bismuth at a temperature ofabout C. and gaseous substantially anhydrous hydrogen chloride feed intothe sulphuric ester-sulphuric acid mixture thereby produced at a,temperature of about 96 C.

17. A continuous process for the manufacture of ethyl chloridewhichcomprises absorbing ethylene in sulphuric acid of a concentrationof to 100%, adding e catalyst or the class consisting of compounds ofantimony, tin and bismuth, reacting the resulting sulphuricester-sulphuric acid mixture with substantially anhydrous gaseoushydrogen chloride et a. temperature of 40 to C., continuously distillingoff formed ethyl chloride and returning the sulphuric acid-conteiningresidue to the ethylene absorption stage. i

18. A continuous process for the manufacture or ethyl chloride whichcomprises sbsorblng ethylene in sulphuric acid of a concentration of95to 109%, adding a. catalyst of the class consisting of compounds oiantimony, tin and bismuth, reacting the resulting sulphuricester-sulphuric scidmixture with substantially anhydrous gaseoushydrogen chloride at substantially atmospheric pressure at a.temperature of 40 to 110 (3., continuously distilling oil formed ethylch10- rlde and returning the sulphuric acid-containing residue to theethylene absorption stage.

29. A continuous process for the manufacture of ethyl chloride whichcomprises absorbing ethyleue in sulphuric acid of a. concentration of 95to lilo sliding e cstelyst of the class consisting of compounds ofcutimony, tin and bismuth, reectiuu the resulting sulphuricester-sulphuric scid mixture with substantially anhydrousgaseoushydrogen chloride at substantially atmospheric pressure at etemperature of 70 to 96" t1. continuously distilling ofi formed ethylchloride and returning the sulphuric acid-ccntsining residue to theethylene absorption stage.

26. ii continuous process for the manufacture of ethyl chloride whichcomprises introducing ethylene into 95- to 0695 sulphuric sold,contein-, ing s ceitslyst of the class consisting of compounds ofentimcny, tin and bismuth, in an ehsorbet, withdrawing from saidabsorber cresction product, consisting of ethyl sulphuric esters endsulphuric acid, containing between 0.7 mol and 1.2 mole of ethyl groupsper mol of sulphuric acid and introducing it to s. reactor, introducingsuhstsntially anhydrous gaseous hydrogen. chic..- ride into saidreaction. product. maintaining a temperature in said reactor of between40 and 110 6., continuously withdrawing ethyl chloride therefrom andcontinuously recycling to said ubsorher the partially exhausted.reaction product containing ethyl groups in the ratio of about 0.25 molper mol. of sulphuric acid.

EEIGEN sorreem osmrzsusrm. cm woorse.

